The critical nutrients that require special attention are limiting or deficient nutrients. Individual amino acids, for example, are usually not limiting when a feed contains high levels of high quality protein (50%+). However, they can become limiting and critical when protein nutrition is poor.
Lipids, proteins, carbohydrates, minerals, and vitamins can all become limiting nutrients in the absence of a complex, well-balanced diet. Unfortunately, we have limited knowledge of the nutritional needs of most larval organisms and how these needs compare to formulated feeds, their uptake.
Lipids and their importance relative to other nutrients
Much is made of the lipid class profile and fatty acid profile of enriched rotifers, especially HUFAs. This is with good cause. However, before going on I would like to quote Sargent, Toucher and Bell in Fish Nutrition edited by Halvar and Hardy. There is “…the impression that because publications on lipids often dominate research journals and conference proceedings on fish nutrition, lipids are the most important nutrients for fish. They are not. Lipids are neither more nor less important than any other group of nutrients — proteins, carbohydrates, vitamins, or inorganic elements.” They go on to say that we know less about the lipid nutritional requirements of fish than for any other class of nutrients, in part because the can be so complex.
Reed Mariculture’s Nutrition Philosophy
Reed Mariculture’s approach to nutrition is to start with proven natural microalgal feeds and to provide them in as unrefined a state as possible. Thus, our “Whole Cell, Whole Food” approach to nutrition.
Next, Reed Mariculture combines our different feed microalgae to create feeds that produce rotifers that most closely match the needs of the larval fish, as estimated primarily from the content of healthy fish eggs as well as the content of common natural prey organisms. We follow this approach for fatty acids, lipid class, carotenoids, sterols, vitamins and any other nutrient we can identify.
Below is a chart of some of the nutritional parameters of some fish eggs, enriched rotifers grown on RotiGrow Plus and enriched with N-Rich, and Production Rotifers grown on RotiGrow Nanno and RotiGrow Plus. The information is incomplete, but nevertheless instructive.
Table B.1 Nutritional Parameters